Rose cyanidin 3,5-di-O-glucoside-assisted gold nanoparticles, their antiradical and photocatalytic activities

Cyanidin 3,5-di-O-glucoside anthocyanin was extracted from red rose flower petals and used as reducing and capping agent for the green synthesis of anisotropic gold nanoparticles (Au NPs). Transmission electron microscope (TEM) images indicated that the Au NPs have large number of small spheres of gold. Surface plasmon resonance band position strongly depended on the [HAuCl4] and [anthocyanin]. Cationic surfactant distinctly changed the shape, size, number of NPs, and size distribution of Au nanodisks at room temperature. Conventional techniques were used to the estimate the antiradical and antimicrobial activities of the cyanidin 3,5-di-O-glucoside anthocyanin and gold NPs. The 2,2-diphenyl-l-picrylhydrazyl nitrogen radical (DPPHGreek ano teleia), two bacteria strains (Staphylococcus aureus and Escherichia coli), and two yeast strains (Candida albicans ATCC 10231 and Candida parapsilosis ATCC 22019) were used to determine the antioxidant and antimicrobial properties of CTAB-capped gold NPs. Eosin yellow photocatalytic degradation followed apparent first-order kinetics with activation energies of 54.4 kJ/mol and 39.5 kJ/mol, respectively, for oxidative and sunlight catalyzed paths. The photocatalytic rates drastically inhibited with scavengers, demonstrating that the reactive radical oxygen species (HO center dot and O-2(-)center dot), holes (h(+)) and electrons (e(-)) played major role in the degradation.